With just 16 days remaining until large-scale military budget cuts are slated to kick in across the force, the Pentagon's top brass went to Capitol Hill on Tuesday with an urgent plea for lawmakers to pass an emergency law halting the so-called sequestration of Defense Department funding.

"It would be immoral to use the force unless it is well-trained, well-led and well-equipped. And we are on that path," Army Gen. Martin Dempsey, chairman of the Joint Chiefs, told the Senate Armed Services Committee.

If Congress takes no action, the budget cuts become real on March 1 and would shave nearly 10 percent off the planned military spending over the next decade. But since the current fiscal year is nearly half over, the impact will be magnified by the need to impose the bulk of those cuts in a compressed timeframe during the second half of the year.

"It will put the nation at risk of coercion and it will break faith with the men and women who serve this nation in uniform," Dempsey said.

Across the force, preliminary cost-cutting measures are already emerging. Most travel for temporary duties has been halted. The Army and Marine Corps are scaling back training. The Navy is canceling deployments and keeping ships in home ports. The Air Force is cutting back on flying hours.

Barring a breakthrough from Congress, other measures will soon follow. Basic funding for fuel and ammunition will be cut, severely impacting training. Defense Department civilians will be furloughed, most likely for 22 days from April to September. In many cases, military personnel will pick up the slack. Maintenance of military equipment could be delayed. Modernization and force structure plans will be reviewed for a new round of long-term cuts, officials say.

The White House has ordered military personnel funds to be exempted from the budget cuts, protecting military paychecks for now. And Pentagon leaders say they will also prioritize funding for operations in Afghanistan and other forward-deployed units as well as wounded warrior programs.

Yet that puts greater pressure on funding for operations, maintenance and training, which will bear the brunt of the cuts. Training schools would cancel classes and commanders would cancel large-scale exercises. Pentagon leaders would raid training and operational accounts that are deemed to be not essential.

In the Army, the budget cuts will result in reduced training for about 80 percent of the active force, and over the next several years they will force Army leaders to shed an additional 100,000 soldiers, or about 20 percent of end strength, under current plans, official said.

Army Chief of Staff Gen. Ray Odierno compared the potential crisis to what the Army faced in the wake of the Vietnam War in the late 1970s. "I began my career in a hollow Army and I do not want to end my career in a hollow Army," he told lawmakers.

The Navy may have offered a window on the future last week when it canceled the deployment of the Harry S. Truman carrier strike group and its roughly 5,000 sailors who were headed to the U.S. Central Command region.

Sen. John McCain, R-Ariz., said the Navy's canceled deployment sends the wrong message to Iran, which is threatening to develop a nuclear weapon. "The signal we are sending to the Iranians is ‘Don't worry, this aircraft carrier is not coming,' " McCain said at the hearing.

Navy officials say the sequestration of funding will force them to shut down several air wings, whose pilots will soon lose their flying certification due to a lack of flying hours. The Navy will have to notify shipyards that maintenance and overhauls will be delayed or canceled. "We will immediately begin to erode the readiness of our force," said Adm. Mark Ferguson, vice chief of naval operations, at the Senate hearing.

For the Marine Corps, individual infantry units would see cutbacks in the fuel and ammunition that are necessary for routine training, said Gen. James Amos, the Corps' commandant. Major equipment maintenance may soon be delayed, large training exercises will be canceled and aircraft will be essentially inactive due to a lack of use and upkeep, Amos said.

For the Air Force, the budget cuts would mean cancelling about 200,000 flying hours this year, including missions overseas such as joint training with allied militaries and the continuous bomber presence over the Pacific. Some test ranges would be closed this summer. Many squadrons will be "completely non-mission capable by July," said Air Force Chief of Staff Gen. Mark Welsh.

The Air Force pilot training pipeline that prepares the new generation of pilots may be shut down by the end of the fiscal year in September. "In a sense we are eating our seed corn" Welsh said.

Operations in Afghanistan initially will be protected. The Army is setting aside money to train units scheduled for near-term deployment, but the units that could replace them, most likely in 2014, are facing training cutbacks and reduced readiness, Odierno said. "We would have to make a decision somewhere along the lines to either extend the units that are there already or send people who are not ready," he said.

Odierno added that he would probably prefer to extend the deployed units rather than send troops into combat who might be poorly trained and equipped.

Outside experts note that even if the so-called sequestration takes effect, the budget cuts will be substantially smaller than those the U.S. military absorbed after World War II, the Korean War and the Vietnam War.

Sequestration comes on top of previously planned military spending reductions that were set in motion in 2011. The potential for the sequestration of defense funding stems from a 2011 budget agreement by Congress.

The severity of the cuts was intended to motivate lawmakers to reach a new agreement to address the nation's budget deficit. However, Congress has been unable to reach any new agreement, increasing the likelihood that sequestration will actually kick in on March 1.

"What is particularly tragic is that sequestration is not the result of an economic recession or an emergency," said Robert Hale, the Pentagon's top financial officer. "All this is purely collateral damage of political gridlock."